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[操作系统]iOS开发_Objective


大体上,OC中常用的数组排序有以下几种方法:sortedArrayUsingSelector:;sortedArrayUsingComparator:;sortedArrayUsingDescriptors:。

 

1、简单排序(sortedArrayUsingSelector:)
如果只是对字符串的排序,可以利用sortedArrayUsingSelector:方法就可以了,代码如下
 

//简单排序


1 void sortArray1(){2 3   NSArray *array = [NSArrayarrayWithObjects:@"abc",@"456",@"123",@"789",@"ef", nil];4 5   NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(compare:)];6 7   NSLog(@"排序后:%@",sortedArray);8 9 }

 

 


当然,除了利用字符串自带的compare:方法,也可以自己写compare:方法,进行对象的比较;如下:
 
首先是新建了 Person 类,实现方法如下(头文件就省了):
 
 1 #import "Person.h" 2  3 @implementation Person 4  5  6  7 //直接实现静态方法,获取带有name和age的Person对象 8  9 +(Person *)personWithAge:(int) age withName:(NSString *)name{10 11   Person *person = [[Person alloc] init];12 13   person.age = age;14 15   person.name = name;16 17   return person;18 19 }20 21 22 23 //自定义排序方法24 25 -(NSComparisonResult)comparePerson:(Person *)person{26 27   //默认按年龄排序28 29   NSComparisonResult result = [[NSNumber numberWithInt:person.age]compare:[NSNumber numberWithInt:self.age]];//注意:基本数据类型要进行数据转换30 31   //如果年龄一样,就按照名字排序32 33   if (result == NSOrderedSame) {34 35     result = [self.name compare:person.name];36 37   }38 39   return result;40 41 }42 43 44 45 46 47 @end

 

 


主函数代码如下:
 
 1 void sortArray2(){ 2  3   Person *p1 = [Person personWithAge:23 withName:@"zhangsan"]; 4  5   Person *p2 = [Person personWithAge:21 withName:@"lisi"]; 6  7   Person *p3 = [Person personWithAge:24 withName:@"wangwu"]; 8  9   Person *p4 = [Person personWithAge:24 withName:@"liwu"];10 11   Person *p5 = [Person personWithAge:20 withName:@"liwu"];12 13   NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil];14 15   NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(comparePerson:)];16 17   NSLog(@"排序后:%@",sortedArray);18 19 }

 

2、利用block语法(sortedArrayUsingComparator:)
苹果官方提供了block语法,比较方便。其中数组排序可以用sortedArrayUsingComparator:方法,代码如下:
 
 1 void sortArray3(){ 2  3   NSArray *array = [NSArrayarrayWithObjects:@"1bc",@"4b6",@"123",@"789",@"3ef", nil]; 4  5   NSArray *sortedArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) { 6  7      8  9     //这里的代码可以参照上面compare:默认的排序方法,也可以把自定义的方法写在这里,给对象排序10 11     NSComparisonResult result = [obj1 compare:obj2];12 13     return result;14 15   }];16 17   NSLog(@"排序后:%@",sortedArray);18 19 }

 


 
 
 
3、高级排序(sortedArrayUsingDescriptors:)
如果是这样一种情况呢?Person类里有另外一个类的变量,比如说Person类除了name,age变量,还有一辆车Car类型,Car类里有个name属性。对Person对象进行排序,有这样的要求:按照Car的name排序,如果是同一辆车,也就是Car的name相同,那么再按照年龄进行排序,如果年龄也相同,最后按照Person的name进行排序。
 
上面这样就要使用第三种方法,利用排序描述器,不多说,有兴趣可以看看API介绍。代码如下:
 
首先写个Car类,实现类Car.m代码如下:
 
#import "Car.h"@implementation Car +(Car *)initWithName:(NSString *)name{  Car *car = [[Car alloc] init];  car.name = name;  return car;} @end

 

 


然后改写Person类,实现类Person.m代码如下:
 
 1 #import "Person.h" 2  3 #import "Car.h" 4  5 @implementation Person 6  7  8  9 +(Person *)personWithAge:(int)age withName:(NSString *)name withCar:(Car *)car{10 11   Person *person = [[Person alloc] init];12 13   person.age = age;14 15   person.name = name;16 17   person.car = car;18 19   return person;20 21 }22 23 24 25 //这里重写description方法,用于最后测试排序结果显示26 27 -(NSString *)description{28 29   return [NSString stringWithFormat:@"age is %zi , name is %@, car is %@",_age,_name,_car.name];30 31 }32 33 34 @end

 


 


主函数代码如下:
 
 1 void sortArray4(){ 2  3   //首先来3辆车,分别是奥迪、劳斯莱斯、宝马 4  5   Car *car1 = [Car initWithName:@"Audio"]; 6  7   Car *car2 = [Car initWithName:@"Rolls-Royce"]; 8  9   Car *car3 = [Car initWithName:@"BMW"];10 11   12 13   //再来5个Person,每人送辆车,分别为car2、car1、car1、car3、car214 15   Person *p1 = [Person personWithAge:23 withName:@"zhangsan"withCar:car2];16 17   Person *p2 = [Person personWithAge:21 withName:@"zhangsan"withCar:car1];18 19   Person *p3 = [Person personWithAge:24 withName:@"lisi"withCar:car1];20 21   Person *p4 = [Person personWithAge:23 withName:@"wangwu"withCar:car3];22 23   Person *p5 = [Person personWithAge:23 withName:@"wangwu"withCar:car2];24 25   26 27   28 29   //加入数组30 31   NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil];32 33   34 35   //构建排序描述器36 37   NSSortDescriptor *carNameDesc = [NSSortDescriptor sortDescriptorWithKey:@"car.name" ascending:YES];38 39   NSSortDescriptor *personNameDesc = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];40 41   NSSortDescriptor *personAgeDesc = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES];42 43   44 45   //把排序描述器放进数组里,放入的顺序就是你想要排序的顺序46 47   //我这里是:首先按照年龄排序,然后是车的名字,最后是按照人的名字48 49   NSArray *descriptorArray = [NSArrayarrayWithObjects:personAgeDesc,carNameDesc,personNameDesc, nil];50 51   52 53   NSArray *sortedArray = [array sortedArrayUsingDescriptors: descriptorArray];54 55   NSLog(@"%@",sortedArray);56 57 }

 

 


结果如下:
 
 
 
从结果看出,先按照age排序,如果age相同,按照car排序,如果car相同,按照name排序。
 
(注意:上面两种排序方法要想实现字符串显示,请重写description方法)
 
 
原博客地址: http://850361034.blog.163.com/blog/static/32803809201436111445914/

 

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